It’s particularly important that people who will be around newborns are vaccinated for whooping cough, said State Health Officer Dr. Ron Chapman.

The California Department of Public Health is reporting that whooping cough has claimed the lives of three infants and sickened more than 4,000 people as the spread of the disease continues to grow.

In the past two weeks, 1,100 new cases of pertussis, also known as whooping cough, have been reported to the CDPH. This brings the total number of cases to 4,558 as of June 24.

One death has been reported in a 2 month-old infant who was 5 weeks old at time of disease onset, according to the CDPH. Two additional deaths occurring in 2014 have been reported; one was a 2-month-old infant who was 4 weeks old at time of disease onset. The other was a 1-year-old baby who was 3 weeks old at time of pertussis onset and hospitalized for more than a year due to pertussis-related complications. Both infants had disease onset in 2013.

Of all the cases reported to the CDPH, 142 have required hospitalization with 28 percent of those needing intensive care. Children 4-months-old or younger account for nearly 2/3 of all pertussis hospitalizations.

“Infants are at the greatest risk of illness and death from pertussis,” said Dr. Ron Chapman, director of the CDPH and state health officer. “Vaccination is the best form of protection. We’re encouraging all parents to vaccinate their children, and for pregnant women to be vaccinated to protect their babies. This will ensure maximum protection against this potentially fatal disease.”

Stanislaus County has reported 42 cases of whooping cough as of June 24. A month ago the county had 22 confirmed cases. Neighboring Merced County had reported four cases, while San Joaquin County had 77.

“Pertussis peaks in incidence every three to five years,” said Chapman. “The last peak in California was in 2010, and now we are concerned that the recent increase in reported cases suggests that another cyclical peak is beginning.”

Toward the end of 2010 California had seen 6, 631 whooping cough cases for the year, which resulted in 10 deaths. All the deaths were children under the age of 3 years. California hadn’t seen such a high rate of whooping cough cases since the 1950s. In Stanislaus County in 2010, there were 153 cases.

Whooping cough is a bacterial infection that attacks the respiratory system. The disease is characterized by severe coughing spasms and last for several weeks, or months. It’s spread from person to person through coughing and/or sneezing. It’s a highly contagious disease that infants and young children are particularly vulnerable to if they haven’t been immunized, the Centers for Disease Control reported.

The CDPH reported that 84 percent of the current confirmed cases have occurred in infants and children. Children between the ages of 7 years to 16 years account for 71 percent of all the pediatric cases in the state.

The Tdap vaccination for pregnant women is the best way to protect infants who are too young to be vaccinated. All pregnant women should be vaccinated with Tdap in the third trimester of each pregnancy, regardless of previous Tdap vaccination. Inoculated women pass immunity to their unborn babies that protect them until they can be vaccinated. Infants should be vaccinated as soon as possible. The first dose of pertussis vaccine can be given as early as 6 weeks of age.

Older children, pre-adolescents and adults should also be vaccinated against pertussis according to current recommendations.

“It’s particularly important that people who will be around newborns also be vaccinated,” added Dr. Chapman. “This includes babysitters, older siblings, parents and grandparents. When those people are vaccinated they will help protect infants who are too young for immunization.”

To prevent pertussis, CDPH recommends that:

• Pregnant women receive a pertussis vaccine booster during the third trimester of each pregnancy, even if they’ve received it before. Most obstetricians can administer the vaccine, but if not, it is available from the county health services agency.

• Infants should be vaccinated against pertussis as soon as possible. The first dose is recommended at two months of age but can be given as early as 6 weeks of age during pertussis outbreaks. Children need five doses of pertussis vaccine by kindergarten (ages 4-6).

• California 7th grade students receive the pertussis vaccine booster as required by state law.

• Adults receive a one-time pertussis vaccine booster, especially if they are in contact with infants or if they are health care workers who may have contact with infants or pregnant women.